Falling Film Absorber
INTRODUCTION

Efficient gas absorption depends on the following:
1. Intimate contact
2. Efficient Heat Transfer

This is achieved in a Falling Film Absorber which is essentially a shell & tube heat exchanger in which both gas to be absorbed and absorbing liquid flow co-currently downward with extraction of heat by circulation of coolant in the shell. The abssorbing liquid is circulated through a tank till desired concentration is achieved. The liquid flows at such a rate that the tubes do not flow full of the liquid but instead, descends by gravity along the inner walls of the tubes as a thin film. Obviously, this produces a much greater linear velocity for a giver rate flow than could be obtained if the tube flowed full.

The equipment works as a number of water cooled-wall columns in parallel and each tube is provided with distribution system on top to effect uniform distribution of both liquid and gas and also formation of a thin liquid film on the inner surface of the tube.


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 Sr. No.
Nominal Size (mm)
Absorber Area (m2)
No. Of Tubes/Tube OD (mm)
Max. Gas Absorption Rate (Pure HCL)* (Kg/hr)
Max. Acid Prod. Rate (As 30% HCL)( Kg/hr)
Height (m)
 1
80
1.00
4/20
30
100
4400
 2
10L
20L
40
10
20
40
 2
100
1.76
7/20
60
200
4500
 3
150
4.80
19/20
150
500
4600
 4
225
7.80
31/20
250
833
4920
 5
300
15.30
61/20
500
1667
5050
 6
400
36.00
143/2
1175
3917
5300
 7
450
47.00
187/20
1500
5000
5700
 8
600
84.00
333/20
2700
9000
5800